Problem is many modern energy efficient house, in northern climates, are highly insulated, have moisture barriers, and impacted by additional internal moisture.

Many have air circulation. But, I suspect much more additional internal moisture (let's say from drying clothes from a family of four) could contribute to mold issues?

Older homes (and those from the past) had plenty of air leaks, little insulation, and had few of these issues to be concerned about.